1. Field of the Invention
The invention relates to the development of Li-ion batteries, and more specifically, to the use of quantum simulations and modular analysis of composite solid solution cathode and alloyed anode materials structures for rapid development of Li-ion batteries.
2. Background of the Invention
Advanced batteries substantially impact the areas of energy storage, energy efficiency, hybrid and plug-in electric vehicles, power tools, laptops, cell phones and many other mobile electronic and entertainment devices. Rechargeable lithium-ion batteries offer the highest energy density of any battery technology and, therefore, are an attractive long-term technology that now sustains a billion-dollar business. At the materials level, over the last 30 years the major improvement in the performance of lithium batteries has been achieved through the discovery of new lithium cathode materials. LiTiS2 was the first commercialized cathode material for lithium batteries in the 1970s. LiCoO2 is currently the most active cathode material used in lithium-ion batteries since its discovery in the early 1990s.
However, the safety and high cost of cobalt significantly limits its application to the emerging high capacity and high power battery markets. Additionally, the low charge and discharge rate capability is a well-known problem of lithium-ion batteries. Recent efforts in both industrial and academic communities to overcome these limitations have been focused on compositional modification of LiCoO2, mainly by infusion with other transition metal elements, or new architectures for advanced composite materials for cathodes.
There has been an interest in the development of an advanced anode using alloyed materials since commercialization of the graphite anode accompanying the LiCoO2 cathode in the 1990s. Alloyed materials for an advanced anode and composite materials for an advanced cathode are the mainstream approach for next generation Li-ion battery technology. Both have the same nature of disorder, in contrast to the well-defined crystalline structures of LiCoO2 and graphite.
Searching for new materials by empirical experimental efforts is time-consuming and expensive. Significant efforts are currently underway, mainly in the academic community and Department of Energy laboratories to use quantum simulations (QS) on high performance computers to accelerate the search for new and better materials for the battery industry. Quantum simulations, based on the first-principles density functional theory (DFT) or its equivalent, provide reliable computer simulations to predict on atomic-scale the properties of currently known battery materials for cathodes, anodes and electrolytes. The accuracy of the QS-based predictions of materials properties has been proven in a broad range of applications (e.g., semiconductors and pharmaceuticals.)
QS-based first principle DFT methods provide reliable information about the materials structures and the energy associated with making structural, electronic, and ionic changes in the materials. The typical QS methods, however, are time consuming, CPU intensive, and do not scale well with the size of the system simulated using QS. Few selected cases of Li-ion battery electrode materials in the layer oxide, spinel, and olivine class have been investigated using DFT-based QS (QS-DFT). The typical QS-DFT methods for thousands of compositional variations in the layer oxide, spinel, olivine, and their composites are not feasible with the current technology.